Mapping Snowmelt and Snow Water Equivalent in Arctic Alaska using Microwave Remote Sensing

The transition from snow cover to snow free conditions for the Arctic land surface is the most significant event in the Arctic hydrologic cycle. Due to the spatial scale and inhospitable conditions characteristic of this region, classification of the transition and estimates of snow water equivalent (SWE) are best made with remote sensing techniques. In particular, microwave remote sensing has the advantages of imaging through the frequent cloud cover and long polar nights. Electromagnetic energy at these wavelengths is also extremely sensitive to the presence or absence of free water in a snowpack enabling the timing and extent of snowmelt to be mapped. Remote sensing techniques using a variety of microwave sensors to derive snowpack conditions for the North Slope of Alaska will be presented. The spatial and temporal progression of snowmelt is mapped from both active and passive microwave spaceborne sensors. One such snowmelt map, for the Kuparuk River Basin, is coupled to a snowmelt runoff model (SRM) to simulate the spring-time hydrograph. SWE estimates from microwave remote sensing are also evaluated on the North Slope.